Playboy model and former 'Girls Next Door' star Kendra Wilkinson is reconsidering her marriage to Hank Baskett -- and marriage in general. What happened? A new preview for 'Kendra on Top' shows that there may be some trouble in paradise.

During a bit of a debate, Wilkinson told her husband of four years (and father of Hank Baskett IV, who will turn 4 in December), "I shouldn't even be married."

Baskett responded by suggesting the couple should "just be single and live together." Uh, okay? Wilkinson's reaction was far different from that of most other women. she retorted, "So you're asking for a open relationship? I've been waiting for this day my whole life!"

Soon, Wilkinson runs into an ex who makes the open marriage idea seem even more appealing than it was before -- and he isn't too thrilled about that. "You were the one who brought up open marriage," Wilkinson snapped at Baskett. He fired back, "You were the one who took off with it!"

Of course, we're going to have to tune in to see how it plays out -- but we're betting they stick it out.